Fragrances are composed of one or more volatile compounds, which can be continuously emitted from simple solutions and dry mixes to which they have been contained to provide a pleasant odor. Rate of fragrance emission is controlled by the delivery system in which fragrances are incorporated in. For example, a delivery system which carries fragrances in pure oil form may provide a surge release of the fragrances, while a delivery system containing encapsulated fragrances may provide a sustained release of the fragrances over an extended period of time.
Fragrances can be added to laundry care, dishwashing, and other home care products to provide a fresh, clean impression for the products and for the subjects treated with the products. In particular, fragrances are an important ingredient in successful commercial fabric care products because many consumers desire fragrances to be deposited on fabrics and remain on the fabrics for a longer length of time in order to convey a continuing impression of freshness.
Fragrances may be delivered together with a detersive agent during a wash cycle. For example, United States Patent Application Publication Nos. 2007/0111919 and 2011/0190191 disclose aggregate detergent granules in which fragrance encapsulates are anchored to detersive particles. The detergent granules can deliver fragrances and a detersive agent to fabrics simultaneously during a single wash.
However, fabrics may still have an undesirable smell or simply lack of a sufficient fresh smell after a wash cycle. To resolve the issues, fabrics may be treated with fabric softeners, and/or by additional treatments that are separate from their washing, to impart an esthetically pleasing odor. The treatments can be done, for example, in a washer during an added rinse cycle, or in a dryer. The separate treatments may employ solid or liquid fragrance compositions. A common problem of solid fragrance compositions is that they can be brittle and difficult to handle and/or manufacture.
U.S. Pat. No. 5,324,444 discloses a process for making free flowing perfume capsule compositions. The perfume capsule compositions essentially contain encapsulated perfumes and water, with the encapsulated perfumes being the major component, in an amount from about 80% to about 99% by weight of the composition. During the manufacturing process, silicon dioxide particles are added to the mixture of encapsulated perfumes and water, at the last manufacturing step, to dry the mixture and improve the flow property of the final capsule powders.
Since only a very small quantity of perfumes is needed to impart a pleasant odor in each laundry treatment, perfume capsule compositions which have a high concentration of perfume, for example as disclosed in U.S. Pat. No. 5,324,444, are not desirable for direct application onto fabrics. This is because dose accuracy may be compromised because of the difficulty in measuring and transferring a very small amount of the highly-concentrated materials. In fact, U.S. Pat. No. 5,324,444 discloses that the perfume capsules are used to prepare a stock detergent composition such that the perfume concentration is significantly diluted. Specifically, about 1% of the highly-concentrated perfume capsule composition is added to a detergent formulation to prepare the stock detergent composition which, in turn, is used for fabric treatment.
U.S. Pat. Nos. 7,867,968 and 7,871,976 relate to scent additives for textiles which comprise from about 80% to about 90% by weight of polyethylene glycol (“PEG”) and from about 4% to 24% by weight of one or more free and/or encapsulated perfumes. The scent additives may be used directly to deliver fragrances to textiles. However, the manufacturing process of the scent additives requires a high processing temperature to melt PEG and keep it molten for mixing with perfumes.
Accordingly, there remains a need for solid compositions to effectively and conveniently deliver fragrance to textiles. Preferably, the solid fragrance compositions can be easily prepared. More preferably, the solid fragrance compositions are storage stable, not brittle, and have an improved flow property profile.